This invention relates to foam dispensing devices and more particularly to foam producing devices for use with fluids which tend to clog the pores of conventional foam dispensing devices said devices also permitting the dispensing, if desired, of the fluid as a liquid rather than a foam.
Numerous foam dispensing devices of a non-aerosol type, which are essentially hand held squeeze bottles of relatively small capacity, have been described in, e.g., U.S. Pat. Nos. 3,709,437 and 3,937,364. However, their characteristics cannot be extrapolated to devices of economically desirable large capacity. This is due to the fact that pressure and liquid capacity control is difficult to achieve in view of the small size required in the foam producing means to produce the most desired foams.
U.S. Pat. No. 4,531,660 describes a device intended to overcome the above disadvantages by placing a small inner chamber, associated with the foam producing means, said combination maximizing the foam quality, within a large chamber or reservoir of economically desirable large capacity.
However, said devices suffer from the disadvantage, by virtue of the foam outlet means being part of the foam producing means must precede it with the concomitant result, that with certain fluids, such as Povidone.TM., the pores of the foam producing means are ultimately clogged. This is a consequence of the foams (i.e., the foamable liquid and gas) having to pass through the pores of the foam producing means.
In addition, as the foam producing means are inserted within the mouth of the foam dispensing device it is necessary to package the foamable liquid and foam producing means as a single unit whereby portability and versatility are descreased.
It is believed, although the theory is not essential to the practice of the invention, that fluids, such as Povidone.TM., which are based on polymeric materials, clog the pores of the foaming means by separation and buildup of the polymeric moieties upstream of and/or within the pores.
It is to be understood throughout the application that references to air and gas may be used interchangably and that the term gas refers to inert gases such as nitrogen.
Furthermore, the described invention makes no provision for dispensing the foamable liquid in a liquid form, if desired, as an alternative to the foam form.
The instant invention to the contrary obviates the above difficulties in that the mixing of the foamable liquid and gas occurs only outside of the container, or reservoir and outside (i.e., downstream) of the pores of the foam producing means. Thus, only the foam producing gas passes through the pores of the foam producing means, when desired, to mix with the foamable liquids to form foams which do not pass through any porous materials after formation.
It is to be understood throughout the application that references to air and gas may be used interchangably and that the term gas refers to inert gases such as nitrogen.